I would like to know why segregated solver is taken for incompressible flow instead of coupled solver

First of all, you should specified what type of solver in terms of method, formulism, etc.

The old approach, i.e. the segregated solver, was a consequence of limited computer capacity mainly in terms of memory. It is possible to observe a new trend in the development of high performance solver based on the partially or fully couple approach.

Thanks for the reply.I am working on simulation of steady state incompressible turbulent flow over a backward facing step.Fluent literature says it is customary to use segregated solver for incompressible flow.But there are no technical reasons for it.I need them.